Automated analysis of digitized electrocardiogram (ECG) signals has various applications. Algorithms operating in real-time with the ability to deal with lead limited signals are useful in external defibrillators and lead-limited monitoring systems. They can be also used, as described here, in long-term ECG telemetry applications.
In the case of a lead limited ECG, it is difficult to automatically distinguish between normal QRS complexes and pathological ECG peaks representing ventricular contractions. Usually pathological complexes are significantly wider and have larger amplitude than normal QRS complexes; however in some cases the situation may be the opposite. A decrease in the number of leads causes the number of misinterpreted events to increase due to a stronger influence of noise and parasite impulses in the signal. In a single lead analysis, it is extremely difficult to distinguish between parasite peaks and QRS complexes due to the lack of additional leads, which are typically used for reference or comparison.